update USWDS from 1 to 3

[nick-mon1]

Plain Language is currrently somewhere on USWDS 1.3.1 to 1.4.3.
Updating from USWDS 1 to 3 will require substantial refactoring if we want to keep the site up to date.

• consider removing uswds-jekyll in favor of USWDS 3 packages
• update component class names
• will also include moving to search.gov
• would require 1-2 weeks of refactoring

[nick-mon1]

This will be closed out when site is migrated.